Apple today completed the final stage of its U.S. iPad rollout. The iPad Wi-Fi + 3G models are now available for sale in Apple stores, online and in most Best Buy outlets.

Those who purchase the 3G iPad will be able to prepay for monthly access to AT&T's network. A 250 MB per month plan costs $14.99, or users can get unlimited data for $29.99 per month.

The iPad is available in Wi-Fi models in the United States for $499 for 16 GB, $599 for 32 GB and $699 for 64 GB. The Wi-Fi + 3G models will be available for $629 for 16 GB, $729 for 32 GB and $829 for 64 GB.